Mobile telephone networks form nowadays an essential part
of the basic infrastructure of a country. The majority have long become accustomed to being
able to use mobile telephones everywhere and at all times. However the setting up of new
mobile telephone transmission units meets increas-ingly frequently with massive resistance
from the local population. In order to improve the acceptance of the further network extensions,
the mobile telephone operating companies have taken the initiative and already de-clared
themselves willing in a voluntary statement made to the Bavarian State Government that they
will set up new transmitters consensually with the towns and communities. In addition, they
wish to minimise the number of the required locations on the basis of the currently valid
limit values by joint usage – in as far as this is permitted under antitrust laws.
As the Federal Government has, with respect to the extensions of the mo-bile telephone
networks, not yet set in force any regulations, the Free State of Bavaria has gone on the
offensive. Thus the Bavarian Ministry of the Environment has set up a sponsorship fund with
which communities are to be supported in the location search for the unpopular transmission
units. Altogether 4 Million DM will be made available from the budget. The new FEE-Program
provides a 50 percent subsidy and is needed to run until the end of 2002. The subsidy sum
of 5.000 € can be applied for on a one-off basis by all Bavarian towns and communes
from the ministry. Consultancy, the register compilation of excising units, comparable measurements
be-fore and after a construction measure and forecasts by means of calcula-tions are funded.
In order to review whether mobile telephone transmission units conform at the projected
sites to the limit values in the sensitive areas as well, two dif-ferent methods are used:
on the one hand, the comparative measurement of the electromagnetic immission before and
after the building measure and, on the other hand, the forecast by calculation of the wave
propagation by means of calculation.
Even if the first method is used very frequently, it reveals a number of dis-advantages.
In particular the measurements are both time-consuming and expensive if differing radio
transmission services such as D-Netz, E-Netz, UMTS, TETRA-Dienste etc. are to be taken into
consideration in the selec-tion of the site. Moreover the Actual Status can first be established
by means of measurements when the transmission unit has been completed, i.e. the building
measures have been concluded.
Calculations provide considerably quicker and more cost-effective solutions to such questions
is the view of EMC experts of the firm of IABG in Otto-brunn near Munich. The company itself
has an own laboratory, accredited by the Bayerisches Landesamt für Umweltschutz (Bavarian
State Agency for Environmental Protection), for the measurement of electromagnetic fields
in accordance with DIN VDE 0848 and thus knows both methods from its daily business practice.
Thus the expensive investments in infrastructure could be put back for so long until planning
reliability with respect to the actual EMC loading had been achieved. Accordingly the exact
Actual Status is calculated without measurements having to be taken on site, when transmission
performance and radiation direction of existing units are known. A further advantage over
the field measurements is seen by the experts as being the possibility of being able to
determine quickly potential alternative locations for transmis-sion masts by using computational
simulation. From these calculations is clearly demonstrated in which area mobile telephone
transmission units could be operated with which level of performance and at which frequency,
so that in the sensitive areas the proposed limit values could be adhered to.
The results of the calculation are summarised on a map on which the com-pliance of limit
values is clear or the maximum permitted performance of a mobile telephone transmitter unit
can be derived. This map can be used in the negotiations with the mobile telephone network
operators and for objec-tive decision-making within the community.
The basis for the calculation is always an individual and tailor-made topo-logical model
of the community. The data for this model, as is well known to IABG, have long been compiled
for Bavaria and can be procured from spe-cial data banks. Such a digital terrain model describes
completely the three-dimensional morphology of the terrain to a degree of accuracy of a
few centimetres with all its elevations and depressions. There the soil com-position is
deposited for example, i.e. whether it is woodland, meadow, a fallow area or the surface
of a lake. With the help of these details, it is then possible to predict exactly, how the
electromagnetic waves react in the ter-rain, i.e. how and where they are refracted and reflected
in the terrain.
01/14/02
printerfriendly Version |
